Diagnosis System

DIAGNOSIS SYSTEM

1. DESCRIPTION

a. The Supplemental Restraint System (SRS) data and the Diagnostic Trouble Codes (DTCs) can be read through the Data Link Connector 3 (DLC3) of the vehicle. When the system seems to be malfunctioning, use the intelligent tester to check for malfunctions and perform repairs.

2. CHECK DLC3








The vehicle's ECU uses the ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.

If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.






HINT: Connect the cable of the intelligent tester (with CAN VIM) to the DLC3, turn the ignition switch ON and attempt to use the intelligent tester. If the screen displays UNABLE TO CONNECT TO VEHICLE, a problem exists in the vehicle side or the tester side.

- If communication is normal when the tester is connected to another vehicle, inspect the DLC3 on the original vehicle.
- If communication is still not possible when the tester is connected to another vehicle, the problem is probably in the tester itself. Consult the Service Department listed in the tester's instruction manual.

3. SYMPTOM SIMULATION

HINT: The most difficult case in troubleshooting is when no symptoms occur. In such cases, a thorough customer problem analysis must be carried out. A simulation of the same or similar conditions and environment in which the problem occurred in the customer's vehicle should be carried out. No matter how much skill or experience a technician has, troubleshooting without confirming the problem symptoms will lead to important repairs being overlooked and mistakes or delays.




a. Vibration method: When vibration seems to be the major cause.

HINT: Perform the simulation method only during the primary check period (for approximately 6 seconds after the ignition switch is turned ON).

1. Apply slight vibration with a finger to the part of the sensor considered to be the cause of the problem and check whether or not the malfunction occurs.

HINT: Applying strong vibration to relays may open relays.

2. Slightly shake the connector vertically and horizontally.
3. Slightly shake the wire harness vertically and horizontally.
The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.

4. FUNCTION OF SRS WARNING LIGHT

a. Primary check

1. Turn the ignition switch OFF. Wait at least 2 seconds, and then turn the ignition switch ON.

The SRS warning light illuminates for approximately 6 seconds and the diagnosis of the SRS (including the seat belt pretensioner) is performed.

HINT: If trouble is detected during the primary check, the SRS warning light remains on even after the primary check period (approximately 6 seconds) has elapsed.

b. Constant check

1. After the primary check, the center airbag sensor constantly monitors the SRS for trouble.

HINT: If trouble is detected during the constant check, the center airbag sensor functions as follows:
- The SRS warning light illuminates.
- The SRS warning light turns off and then illuminates. This blinking pattern indicates the source voltage drop. After the source voltage returns to normal for 10 seconds, the SRS warning light turns off.

c. Review

1. When the SRS is normal:
The SRS warning light illuminates only during the primary check period (for approximately 6 seconds after the ignition switch is turned ON).

2. When the SRS has trouble, one of the following may occur:

- The SRS warning light remains on even after the primary check period has elapsed.
- The SRS warning light turns off after the primary check, but illuminates again during the constant check.
- The SRS warning light does not illuminate when turning the ignition switch from OFF to ON.

HINT: The center airbag sensor keeps the SRS warning light illuminated if an airbag has been deployed.

5. SRS WARNING LIGHT CHECK




a. Turn the ignition switch ON, and check that the SRS warning light illuminates for approximately 6 seconds (primary check).
b. Check that the SRS warning light turns off approximately 6 seconds after the ignition switch is turned ON (constant check).

HINT: When any of the following symptoms occur, refer to the "Problem Symptoms Table". Symptom Index

- The SRS warning light illuminates occasionally after the primary check period has elapsed.
- The SRS warning light illuminates but a DTC is not output.
- The ignition switch is turned from OFF to ON, but the SRS warning light does not illuminate.

6. RELEASE METHOD OF ACTIVATION PREVENTION MECHANISM

a. The activation prevention mechanism is built into the connector for the squib circuit of the SRS. As explained in the troubleshooting section, insert a piece of paper of the same thickness as the male terminal between the terminal and the short spring to release it (refer to the illustrations below).

CAUTION: Never release the activation prevention mechanism on the squib connector.

NOTE:
- Do not release the activation prevention mechanism unless specifically directed by the troubleshooting procedure.
- To prevent the terminal and the short spring from being damaged, always use a piece of paper of the same thickness as the male terminal.

7. FUNCTION OF PASSENGER AIRBAG ON/OFF INDICATOR

a. Initial check

1. Turn the ignition switch ON.
2. The passenger airbag ON/OFF indicator comes on for approximately 4 seconds, then goes off for approximately 2 seconds.







3. Approximately 6 seconds after the ignition switch is turned ON, the passenger airbag ON / OFF indicator will operate according to the front passenger seat condition shown below.

HINT:
- The passenger airbag ON/OFF indicator is based on the timing chart below in order to check the indicator light circuit.
- When the occupant classification system has trouble, both the SRS warning light and the passenger airbag ON/OFF indicator ("OFF") come on. In this case, check the DTCs in "AIRBAG SYSTEM" first. Then troubleshoot the occupant classification system if DTC B1650/32 is detected, and troubleshoot the passenger airbag ON/OFF indicator if DTC B1660/43 is detected.

8. PASSENGER AIRBAG ON/OFF INDICATOR CHECK







a. Turn the ignition switch ON.
b. Check that the passenger airbag ON/OFF indicator ("ON" and "OFF") comes on for approximately 4 seconds, then goes off for approximately 2 seconds.

HINT: Refer to the table in the previous step regarding the passenger airbag ON/OFF indicator when the ignition switch is turned ON and approximately 6 seconds have passed.

9. ACTIVATION PREVENTION MECHANISM

a. FUNCTION OF ACTIVATION PREVENTION MECHANISM

1. An activation prevention mechanism is built into the connector (on the center airbag sensor side) of the airbag system squib circuit to prevent accidental airbag activation.
2. This mechanism closes the circuit when the connector is disconnected by bringing the short spring into contact with the terminals and shutting off external electricity to prevent accidental airbag activation.

b. RELEASING OF ACTIVATION PREVENTION MECHANISM

1. To release the activation prevention mechanism, insert a piece of paper with the same thickness as the male terminal (approximately 0.5 mm (0.020 in.)) between the terminals and the short spring to break the connection.

2. Refer to the following illustrations concerning connectors utilizing the activation prevention mechanism and its release method.








CAUTION: Never release the activation prevention mechanism on the squib connector even when inspecting with the squib disconnected.

NOTE:
- Do not release the activation prevention mechanism unless specially directed by the troubleshooting procedure.
- To prevent the terminal and the short spring from being damaged, always use a piece of paper with the same thickness as the male terminals.